kid’s fleece/insulation

Lands End makes excellent down jackets and vests. My son has worn them, and they don't fall apart! LLBean, Lands End and Campmor for fleece. LE is usually very affordable. They also sell soft shells, etc.
I found an excellent soft shell at Target this year also.
Pants and tops? Target and Wal mart are the places. I can get Champion tops for $8-10, hiking pants for $8-15.

Something to keep in mind is:

(1) Kids grow pretty quickly, so expect your clothing investments to last at most a couple of years

(2) I doubt any kids will be sufficiently careful with gossamer materials we often seek in our maximum warmth / weight. This means you should expect their clothing to be heavier than you might wish.

My suggestions would be:

Every couple of weeks check sierra trading post for new items. They typically don't have a lot of good kids stuff. But time to time they have some real jems. I think we picked up my daughter's beloved marmot Driclim Windshirt for somethimg like $15. Much of my daughte's outdoor clothing has come from STP. As to other source… Land's End has been one of the most reliable sources for us. L.L. Bean and Campmor has been useful. REI has been a so/so source. Their stock is often limited and it's rare that the stuff we are interested in stays in stock long enough to be priced down in end of season clearance sales.

In general, I wouldn't get down for kids because most won't be sufficiently careful to keep it dry. The last time I looked, REI, North Face, and L.L. Bean has some reasonable looking down clothing for smaller kids. Obermeyer makes decent ski warm, but it their stuff tends to be heavier than I would choice for backpacking since it is designed to survive kids learning to ski.

Lands End down jackets are DWR covered btw. My son has been in downpours and that jacket has come thru singing. It is worth it, and also, LE has clearance sales online where often down jackets end up in spring!

..I found some amazing deals there. It misses some sales, but generally scours all the sites. Choosing the right key words is key.
I don't shop for children, but my girlfriend wears girls size L, so actually I got some great deals on brand name clothes for her. Example, Patagonia capilene tops and bottoms, $15 each.

Sorry I can't point you at a specific source, but here's an example; $6 hooded fleece tops (in this case from Target)
http://www.froogle.com
Notice in the following example I used the "-ebay" keyword, because I dont hassle with auctions and don't trust most of the sellers. Remove it if you like of course.

http://froogle.google.com/froogle?q=fleece+top+girls+-ebay&hl=en&btnG=Search

I appreciate everyones input and will be spending the next couple of months getting a kit together. My only real problem will be in trying to limit the number of stuffed animals that get to go with us.
If you ever see one of my gear lists for a climb there is always one stuffed animal that gets to go with daddy, she expects summit pictures so no ditching allowed.